Services

Kapexy’s experience covers PVT modeling of all types of petroleum reservoir fluids. Below are examples of the fluid modeling services offered.

Table of contents

 

Validation of Fluid Samples

Selection of the right fluid samples for experimental PVT studies is crucial when planning production from a new field. The samples may contain mud contamination from drilling fluids, or the drainage in the near wellbore area may have been so high that samples taken were split into two phases at the sampling conditions.

If gas injection EOR studies are to be performed, a sample volume of approximately 2,000 cc is needed. This may require comingling of individual fluid samples, which must therefore be as close to identical as possible.

Samples taken at different depths will be affected by compositional grading, which can make it challenging to validate samples taken over a large depth range. Kapexy has access to extensive data and highly specialized software that allows predictions of the limits of the compositional variation with depth. This allows Kapexy to perform quality control of the data with respect to variation in fluid composition and fluid properties with depth.

A validation study will be thoroughly documented, clearly specifying the criteria that were used to select fluid samples for PVT studies.

 

 

Fieldwide EoS Modeling

Kapexy offers equation of state (EoS) modeling for single fluids as well as common EoS modeling for multiple fluids. An EoS modeling project starts with quality control of fluid samples and PVT data. Component lumping and model selection are tailored to the customer’s needs.

Liquid dropout curves and gas injection swelling data are given much importance, as this data is crucial for the location of the critical point of the fluid, something that affects the fluid phase behavior even far from the critical point.

It is possible to include an analysis of possible communication between different zones located in different depths. As a conclusion to the project, Kapexy offers to generate input tables for black oil and compositional reservoir simulators.

The entire project will be well documented in a report.

Performed by consultants with over 30 years of experience, you are guaranteed a high-quality product.

Asphaltene Screening & Modeling Studies

Asphaltene precipitation can occur in the reservoir, in the well or in the process equipment. Experimental asphaltene measurements are costly, and Kapexy offers, based on a compositional analysis and a SARA analysis, to determine whether there is a risk of asphaltene precipitation during production and possible gas injection. If this is the case, Kapexy can in collaboration with the laboratory plan an experimental program to provide the data necessary for Kapexy to subsequently develop a reliable asphaltene EoS model.

An asphaltene modeling project will, in addition to the asphaltene EoS model be delivered with a report with a complete asphaltene phase diagram that makes it easy to determine where in the production process to expect asphaltene precipitation. The effect of possible gas injection may also be covered.

Depth Gradient Modeling

Access to comprehensive data for the compositional variation with depth in petroleum reservoirs worldwide has enabled Kapexy to offer a highly specialized consulting service within depth gradient modeling. A compositional analysis and associated sampling data for a single fluid sample is all that is needed to obtain a reliable representation of compositional variation with depth. With fluid samples taken at different depths, the model can be adjusted to match the observed depth of a possible GOC and how the saturation pressure and GOR evolve with depth as well as the concentration profile of one or more components.

Thermodynamics Course for Reservoir Engineers

This 3-day thermodynamics course will refresh concepts from college studies and introduce the thermodynamic models that PVT packages and reservoir simulators use to calculate phase properties and phase compositions of reservoir fluids. The theory will be accompanied by practical examples that connect it to the PVT tasks faced by a reservoir engineer.

Day 1

  • Cubic equations of state
    • Van der Waals
    • SRK and PR
    • Volume correction
    • Classical mixing rules
  • Phase equilibria
    • Ideal and non-ideal mixtures
    • Henry’s constant
    • Fugacity
    • K-factors
    • Critical point
    • Saturation point calculations
    • PT Flash calculations

Day 2

  • Natural Gases
    • Corresponding states principle
    • GERG-2008 equation of state
  • Reservoir fluid characterization
    • Splitting of plus fraction
    • Equation of state parameters for C7+ components
    • Binary interaction parameters
  • Mixtures with water
    • What makes water special
    • Mathias-Copeman vapor pressure
    • Non-classical mixing rules
    • CPA model

Day 3

  • Thermal properties (H, S, Cp)
    • Enthalpy
    • Entropy
    • Heat capacity
  • Compositional grading
    • Gravity segregation
    • Gas-oil contact
    • Shift of phase type through criticality
    • Impact of temperature gradient
  • CO2 rich mixtures
    • Pure CO2
    • CO2 and hydrocarbons
    • CO2 and water
    • Chemical reactions with CO2

Course material: Book by Pedersen, K.S., Christensen, P.L., Azeem, J., Phase Behavior of Petroleum Reservoir Fluids, 3rd edition, Taylor & Francis, Boca Raton, US, 2024.

Lecturer: Karen Schou Pedersen

For more information, send e-mail to contact@kapexy.com